The long-term objective of this research program is to increase our understanding of how listeners develop the skills to compensate for variability in the speech signal and how hearing loss influences the development of these skills. A listener's ability to perceive speech accurately despite the vast amount of variability in the speech signal is contingent on the flexibility of the speech perception system and its rapid adaptation to novel input. Adults demonstrate robust speech perception in the face of variability but how this skill develops is unknown. This research proposal will investigate this issue by testing children's perception of foreign-accented speech, a common, real-world source of speech variability. The first aim of this research project is to develop a novel digital database of audio-recorded speech materials including words, sentences, and paragraphs appropriate for children as produced by native and non-native speakers of English. This database will serve as a novel resource for future projects on children's and adults'perception of foreign-accented speech. In addition to the audio recordings, the database will include objective intelligibility, subjective comprehensibility, and foreign-accent ratings by adults. Since there are currently no publicly available materials of this kind, this project represents a mandatory first step in investigating the perception of foreign-accented speech in children. The second aim is to compare the developmental trajectory for the perception of native and non-native speech by children with normal hearing between the ages of 3;0 and 8;11. To address this aim, children's perception of foreign-accented speech will be tested in both closed- and open-set tasks. Further, the influence of speech variability on working memory will be assessed with word, letter, and digit span tasks. The third aim of this project is to assess how hearing loss influences the perception of variability in speech by comparing the perception of foreign-accented speech by children with normal hearing and children with bilateral mild to moderate sensorineural hearing loss between the ages of 3;0 and 8;11. The proposed experiments are designed to map out the developmental trajectory of speech perception skill under conditions of high variability and assess how hearing loss impacts the development of these fundamental perceptual skills. Additionally, examinations of children's perception of foreign-accented speech will provide new information for theories of perceptual learning and language acquisition. PUBLIC HEALTH RELEVANCE: Language acquisition, performance in school, and social interactions all require the ability to compensate for the enormous amount of variability in the speech signal introduced by differences across talkers in native language, dialect, age, gender, and emotional state among other factors. Although this skill is essential for successful communication, children with hearing loss may have difficulty mapping unfamiliar, variable sounds and words onto their native categories. Therefore, testing how children with hearing loss perform on word recognition, sentence perception, and working memory tests with foreign-accented speech, a common, real-world source of variability in the speech signal, will more closely simulate real-world complexities and thus will provide more robust measures of their performance outside of the clinic or research laboratory.